experts decision making schemes slide share
DESCRIPTION
Schemes for Expert Medical Decision MakingTRANSCRIPT
Secrets of Experts in Clinical Decision Making: Schemes of
Care
Dr. Imad Salah Ahmed Hassan MD FACP FRCPI MSc MBBS
Consultant Physician & Pulmonologist
Chairman, Knowledge Translation Committee
Department of Medicine
King Abdulaziz Medical City
Riyadh, Saudi Arabia
Step 1 Gather Information (History & Physical)
Step 2 Summarize the Case using Technical Language
Step 2
• Comprehensive but Concise, Text-book-Like:• Must contain patient’s name, gender, age, • ± occupation, ± nationality ± racial/geographic
origin, relevant Past History/Social History/Family History, Drug/Allergic History, Symptoms + duration –in technical terms, Relevant physical signs in technical conclusive terms.
Step 2: Case Presentation Example
• 67 yr old male• Bird/pigeon breeder, smoker• 3 days history of fever, cough with yellow sputum, left
stabbing chest pain that is worse with breathing and coughing and breathlessness
• Clinically, breathless, cyanosed, disoriented to time, person and place, Temperature 39.1C, BP 86/50, RR 32/min, bilateral coarse crepitations, bronchial breathing left lower zone.
• Chest x-ray: left basal consolidation
Step 2: Case Technical Summary
• 67 year old, smoker and bird-breeder presenting with a 3 days history of productive cough, dyspnea and left pleuritic chest pains.
• Clinically confused, cyanosed, febrile, tachypnoiec and hypotensive with signs of left lower zone consolidation.
Step 3 Propose a Diagnosis
Step 3: Use Bed-side Diagnosis Schemes: PR, 3Rs, HD
• Pattern-recognition PR• “ Rules of Thumb” Smart Heuristics• Rule-Out worst Scenario ROWS• Red Flags (symptoms or signs of more serious
pathology-usually after diagnosis is made) etc• Hypothetico-deductive HD Strategies (from H&P)
Step 3: Use Bed-side Diagnosis Schemes
• High-Fidelity/Reliability Pattern Recognition (spot diagnosis): Shingles, Acromegalic Facies
• Low-Fidelity/Reliability Pattern Recognition (error-prone): Central chest pain radiating to the left arm plus sweating, nausea and vomiting =Acute Coronary Syndrome (other possibilities still exist!)
• Smart Heuristic “Rules of Thumb”: early morning headache and vomiting=Increased intracranial pressure
• ROWS: Meningitis, SAH, CVA, Temporal Arteritis etc in a patient with headache
• Red Flags: rest pain, weight loss, neurological deficits etc in a patient with low back pain
Step 3: Use Bed-side Diagnosis Schemes
• Hypothetico-deductive Strategies (from H&P) • Detailed history• Clues from all components of the history• Comprehensive physical examination• May need to revert to investigations if no diagnosis is clear.
Step 4 Differential Diagnosis
Step 4: Use Differential Diagnosis Schemes
• Differential Diagnosis Cognitive Aids: Anatomical Physiological Pathological
An important cause of missing a diagnosis is not thinking of it!!! i.e. not putting a differential diagnosis.
Step 4: Use Differential Diagnosis Schemes
Anatomical Differential Diagnosis
Physiological Differential Diagnosis
Etio-pathological Differential Diagnosis
Pain Syndromes: e.g. central chest pain may be categorized as arising from the heart, aorta, esophagus, chest wall etc
Shock: this may be hypovolemic, distributive, obstructive or cardiogenic
Congenital or Hereditary
Swellings: e.g. a neck swelling differential diagnosis will include the thyroid, lymph nodes, vascular, skin etc
Thrombosis: This may be related to a vessel wall pathology, blood constituents or flow rate.
Acquired: 1. Traumatic 2. Infective: viral, bacterial
etc 3. Inflammatory/auto-
immune 4. Vascular/degenerative 5. Neoplastic/para-
neoplastic 6. Metabolic/endocrine 7. Drug-induced/ poisoning 8. Deficiency diseases 9. Psychogenic 10. Idiopathic/cryptogenic
Step 5 Order Tests (Rationally)
Step 5: Pre-test Probability Assessment for Rational Test Ordering
• Frugal (i.e. simple and applicable) Heuristics Probability Assessment: The AP Scheme
• Order tests: based on Test Sensitivity, Specificity and Likelihood Ratios
• Baye’s may not be a practical and quick pre-test probability assessment approach!
Step 5: Pre-test Probability Assessment for Rational Test Ordering: AP Scheme
• Frugal Pre-test Probability Assessment: The AP Scheme
1. Absent Alternative: No alternative plausible bed-side Diagnosis: Yes/No
2. Presence of Strong Risk factor for the condition: Yes/No
• Interpretation: High Probability (2 YES) or Intermediate Probability(1 YES 1 NO) or Low Probability (2 (both) NO)
Step 5: Pre-test Probability Assessment for Rational Test Ordering
• SpIn: highly specific tests are useful for ruling-in the diagnosis when positive ( use for high and intermediate probabilities) e.g. spiral CT for suspected pulmonary embolism.
• SnOut: highly sensitive tests are useful for ruling-out the diagnosis when negative ( use for low probabilities) e.g. d-dimer for suspected pulmonary embolism.
Sensitivity•How often is
the test result correct for persons in whom the disease is known to be present?
•Sensitivity - the proportion of people
with disease who have a positive test.
SENSITIVITY
•in a group of 100 patients with bacterial pneumonia, 80 had a raised C-reactive protein CRP: the sensitivity of CRP for diagnosing bacterial pneumonia is thus 80%.
Example:
Specificity•How often is
the test result correct for persons in whom the disease is known to be absent?
•Specificity - the proportion of people without the disease who have a negative test.
SPECIFICITY
•in a group of 100 patients without pneumonia, 10 had a raised C-reactive protein CRP: the specificity of CRP for correctly excluding pneumonia is thus 90%.
Example:
Likelihood Ratio•the likelihood that a given
test result would be expected in a patient with the target disorder compared to the likelihood that the same result would be expected in a patient without that disorder.
•In general, a positive likelihood ratio of 4 or more is useful in ruling-in the target disorder. A negative likelihood ratio of less than 0.3 is useful in ruling-out the target disorder.
Likelihood ratio:
Likelihood Ratio•Example: A raised
Jugular venous pressure JVP in a patient with a history suggestive of congestive heart failure CHF has a positive LR of 5.8 and a negative ratio of 0.66. Thus the presence of a raised JVP rules-in the diagnosis of CHF. Its absence is not as useful in ruling it out.
Likelihood ratio:
Step 6Confirm &
Comprehensively give a Diagnostic Label
The BESDiagnosis Scheme
Better diagnostic labeling thereby assisting in implementing individualized, evidence-based interventions.
• 1. The Bed-side Clinical Diagnosis
• 2. The Etiological or Precipitating Cause
• 3. The Severity Score or Grade.
Bedside Clinical Diagnosis
Etiological/
Precipitant
Severity
Guideline-friendly Bed-side Diagnosis, Etiology, Severity (BESD)
“the diagnosis that would explain all the symptoms & signs”
“what is the Cause”
“how bad”• CURB-65: CAP• Killip Classes: ACS• Glasgow CS• Croup Score• APGAR Score• Blatchford score: UGI
bleed• Ranson Score:
Pancreatitis• Emerg. Severity Index
Usefulness of The Scheme• Failure to consider the precipitant or cause in
addition to the clinical diagnosis will inevitably result in deficient care input and a poorer outcome.
• Appropriate evidence-based interventions to optimize outcome according to SEVERITY will be different specifically with regards the sites of care and recommended Immediate Interventions.
Usefulness of The Scheme• e.g.• Usual Label: “Admitted with an asthma
exacerbation…………• Guideline-Friendly Evidenced-Based Label:
1. The Bed-side Clinical Diagnosis: Asthma Exacerbation
2. The Etiological or Precipitating Cause: Poor Inhaler Technique
3. The Severity Score or Grade: Life-threatening Asthma
Usefulness of The Scheme
• e.g. Continued….• Implications:• Site of Care: ICU• Therapy for life-threatening attacks: Oxygen, systemic
steroids, combination nebs etc• Prevention of re-admission: training on inhaler technique
Step 7 Therapeutic Interventions
Step 7: Therapeutic Interventions: The 5S Scheme
• Contextual• Patient-centered
– Therapeutic Cognitive Aid: Site of Care, Symptomatic, Supportive, Specific and Specialty Referral (5S).
Immediate Therapeutic Interventions:The 5S
Site of Care
Symptomatic
Supportive
Specific
Specialty Referral
e.g. CCU
e.g. cardiology
e.g. Analgesics
e.g. thrombolytic
e.g. IV fluids
The 5 S Scheme
• Site of Care: Guidelines, unambiguously dictate sites of care for specific disease severity scores.
• ICU for CURB-65 of 3 or more• CCU for Acute Coronary Syndrome
The 5 S Scheme
• Symptomatic treatment: is important as it directly alleviates patient discomfort.
Analgesia for painAnti-emetics for nausea and vomitingAnti-pyretics for fever
The 5 S Scheme
• Supportive care: to improve physiological derangements before damage becomes irreversible and until the precipitant is brought under control by its specific intervention may be life-saving.
IV Fluids for dehydrationBicarbonate for acidosisOxygen for hypoxia
The 5 S Model
• Specific Care: directed at the primary cause.
Antibiotics for infectionThrombolytics for acute myocardial
infarctionAppendicectomy for acute appendicitis
The 5 S Scheme
The 5 S Model
• Specialty Referral: guidelines recommend early specialty or sub-specialty referral for specific acute illnesses.
GIT team for a patient with hematemesisCardiology for a patient with ACSPhysiotherapy for a patient with stroke
The 5 S Scheme
The complete input: An Example1. Bedside-Clinical Diagnosis Acute BA Exacerbation
2. Precipitant Poor Inhaler Technique
3. Severity Life-threatening
4. Site of Care ICU
5. Symptomatic Bronchodilators
6. Supportive Oxygen, IV Fluids
7. Specific Bronchodilators, Steroids
8. Specialty Referral ICU, Pulmonary, Asthma Educator
Step 8 Prepare for Discharge
Step 8: Prepare for Discharge (ACT)
• Assess Response to Treatment (Subjective & Objective)
• Criteria for Discharge• Timing of Follow-up
The ACT Scheme
• Assess Response to Treatment: Subjective & Objective
• Criteria for Discharge: Clinical, Laboratory, Radiologic, Social etc
• Timing of Follow-up : Clinic Appointment for disease and drug monitoring
Good Luck